Lecture 15 - Communities Flashcards
Community
An assemblage of all the populations of different species living close enough together for potential interactions
Species richness
The number of species in a community
Species diversity
The relative abundance of species in a community
Refers to how common or rare a species is relative to other species
Ecological niche
The sum of a species use of the biotic and abiotic resources in its enviornment
The role a species plays
Fundamental niche
Is the entire set of conditions under which an organism (population, species) can survive and reproduce itself
Realize niche
Is the set of conditions actually used by given organism (pop, species), after interactions with other species (predatioin and competition) have been taken into account
What determines a niche?
Enviornmental conditions
Abiotic
- Climate
- Soils
- Disturbances
What deterines a niche?
Species interactions
Biotic
- Competition
- Mutualism
- Parasitism
- Herbivory
- Predation
Competition
Occurs between populations of two species if they both require the same limited resource
principle of limiting similarity
Mutualism
Two organisms of different species exist in a relationship in which each individual benefits from the activity of the other
Parasitism
Lives on or in host from which it gains nutrients
Endoparasite, Ectoparasite
Herbivory
The consumption of plants by animals
Predation
The consumption of prey by predators
Aposematic Coloration
Honest signal warning potential predators against harm to avoid becoming prey
Mimicry
Take advantage of another organisms’ strategy to gain survival advantage
Can be honest or dishonest
Batesian mimicry
- Dishonest signal
- Non toxic/non-dangerous organism mimics dangerous organism
Mullerian mimicry
- Honest signal
- 2 or more dangerous species share warning coloration
- Converys “message” more efficiently
Disturbance
A temporary change in enviornmental conditions that causes a pronounced change in an ecosystem
fires, natural disasters
Ecological succession
The change in community diversity over time
Primary succession
A biological communty arises in an area without soil
Secondary succession
A disturbance remove vegetation, but there is still intact soil
Keystone Species
A species whose impact on the community is much larger than its biomass or abundance would indiciate
Invasive species
Non-native species that adversely affect the habitats they invade economically or ecologically
What makes a species invasive?
- High reproduction
- Short time to mature and reproduce
- Associate with human acitivites and environmental disturbances
- Good dispersal abilities
- Ability to outcompete native species for resources
- Lack of enemies
